Modern oil field operations demand a great quantity of information relating to the parameters and conditions encountered downhole. Such information typically includes characteristics of the earth formations traversed by the borehole, and data relating to the size and configuration of the borehole itself. The collection of information relating to conditions downhole, which commonly is referred to as “logging,” can be performed by several methods including wireline logging, “logging while drilling” (LWD), drillpipe conveyed logging, and coil tubing conveyed logging. A variety of logging tools are available for use with each of these methods.
One example of an available wireline logging and LWD tool is a high frequency dielectric tool (HFDT). Such tools determine the dielectric constant and conductivity of downhole formations from the real and imaginary parts of the complex propagation constant of electromagnetic waves traveling through the formations. (See, e.g., T. J. Calvert, R. N. Rau and L. E. Wells, “Electromagnetic propagation . . . A new dimension in logging,” presented at the Annual Meeting SPE, Bakersfield, Calif., April 1977, Paper 6542; D. S. Daev, Vysokochastonye Electromagnitnye Melody Issledevity. Skhvazhin:publ.House “Nedra,” Moscow, 1970; and R. A. Meador and P. T. Cox, “Dielectric constant logging, a salinity independent estimation of formation water volume,” presented at the Annual Meeting SPE, Dallas, Tex., Oct. 1, 1975, Paper 5504). The HFDT measurements may be used in accordance with the Complex Refractive Index Method (“CRIM”) to obtain an estimation of the water-filled formation porosity. However, previous applications of this method have implicit assumptions that may lead to inaccurate analysis of formation porosity.